Caracterização microestrutural, mecânica e de desgaste por deslizamento de uma liga Al90Cu4Fe2Cr4 fabricada por conformação por spray

Abstract

In recent years, technological advancements in metallurgy and continuous developments in manufacturing processes have led to extensive research on quasicrystalline and intermetallic alloys and their composites. This is due to the complex atomic structures of these alloys, as well as their unique tribological and thermal behaviors. The main focus of research is to identify viable industrial applications for these alloys. Among quasicrystalline systems, the Al-Cu-Fe-Cr system has stood out, as it is capable of forming stable decagonal quasicrystalline phases, with great potential for industrial applications. This work studied the microstructure and sliding wear behavior of a spray-formed alloy with chemical composition Al90Cu4Fe2Cr4 (at. %). Mechanical properties under compression and Vickers microhardness were also evaluated. The microstructure of the spray-formed material consisted of an α-Al matrix reinforced with two complex intermetallic phases, λ-Al13Fe4(SSCu,Cr) and Al13Cr2(SSCu,Fe), which are binary intermetallic structures, with significant amounts of other alloying elements. The dry sliding wear resistance of the composites was evaluated using a pin-on-disk test configuration, with normal loads ranging from 10 to 20 N and sliding velocities from 0.05 to 0.2 m/s-1. Alumina spheres were used as counter-bodies. The samples displayed notable resistance to sliding wear, particularly under elevated normal loads, and exhibited minimal fluctuations in specific wear rates across all tested parameters, ranging from 7 to 8 x 10-4 mm3/N.m. The friction coefficient also remained relatively constant, hovering around 0.4, across the investigated tribological systems. The primary wear mechanism observed was the delamination of intermetallic particles. These findings suggest an enhanced resistance to dry sliding wear under high normal loads compared to Al matrix composites reinforced with previously produced quasicrystals and complex intermetallic phases. Moreover, the mechanical properties of this alloy, manufactured through a single-step process, demonstrated mechanical characteristics within the same range as those reported in prior studies of Al matrix composites reinforced with quasicrystals and micrometer-sized intermetallics, albeit employing more intricate processing techniques.